Examples of automobiles include gasoline automobiles using gasoline and diesel automobiles using light oil. In addition to these, gas engine automobiles using a fuel gas, such as a compressed natural gas (CNG) or compressed hydrogen, have been known. In the gas engine automobile, the fuel gas is stored in, for example, a high-pressure tank, and the stored fuel gas of high pressure is supplied to a gas engine through a fuel gas supply system. Known as the fuel gas supply system is, for example, a fuel supply apparatus of a gas engine in PTL 1.
The fuel supply apparatus of the gas engine described in PTL 1 includes a fuel injection valve (gas injector), and the fuel injection valve and a bomb (high-pressure tank) are connected to each other by a pipe. On this pipe, a main stop valve, a regulator, and a low-pressure fuel shutoff valve are provided in this order from the bomb side. Each of the main stop valve and the low-pressure fuel shutoff valve can open and close a passage in the pipe. When stopping the gas engine, each of the main stop valve and the low-pressure fuel shutoff valve closes the passage to shut off the supply of the fuel gas to the gas engine. In contrast, when activating the gas engine, each of the main stop valve and the low-pressure fuel shutoff valve opens the passage to allow the fuel gas to be supplied to the gas engine. The regulator reduces the pressure of the high-pressure fuel gas, flowing from the bomb, to predetermined pressure to introduce the fuel gas to the fuel injection valve.
In the fuel supply apparatus of the gas engine configured as above, the fuel gas stored in the bomb flows through the main stop valve to be introduced to the regulator. The fuel gas is reduced in pressure by the regulator and then flows through the low-pressure fuel shutoff valve to be introduced to the fuel injection valve. The fuel injection valve injects to the gas engine the fuel gas, the amount of which corresponds to a command from, for example, an ECU.